bozdoz

<a href="https://wordpress.org/plugins/jetpack/" rel="ugc">Jetpack</a> makes it easy to add contact forms to your WordPress site, but you may want a simple way to add a <a href="https://www.google.com/recaptcha/" rel="nofollow ugc">Google reCAPTCHA</a> to prevent spam. This plugin will manipulate the Jetpack <code>[contact-form]</code> shortcode to prepend the Google script, add a button, and parse the response.
This plugin allows both reCAPTCHA v2 and invisible reCAPTCHA (see screenshots and choose whatever works for you!).
Shoot me a question about it on Twitter: <a href="https://www.twitter.com/bozdoz/" rel="nofollow ugc">@bozdoz</a>.
This plugin is open source on <a href="https://github.com/bozdoz/wp-plugin-recaptcha-jetpack" rel="nofollow ugc">GitHub</a>!

reCAPTCHA Jetpack

A simple plugin that adds a Google reCAPTCHA to the Jetpack contact form. Requires the Jetpack plugin.

Tanner Moushey

Jetpack is an amazing plugin with many great features. Sometimes, however, you just want to use a specific feature from Jetpack and don’t want to go through the hassle of connecting Jetpack to your WordPress.com user account. This is where this plugin comes in handy.
Just install this plugin and you will get access to all of the Jetpack modules that do not require a connection to WordPress.com.
If you find that the module you are interested in is not available after installing this plugin, that is an indication that a WordPress.com account is required for that module. These include Site stats, Publicize, and a few others.

Unplug Jetpack

Jetpack's unnecessary requirement to connect to a WordPress.com account is so frustrating. This plugin removes that requirement for all Jetpack modules that don't really on WordPress.com services.



Better than Jetpack itself!

Use Jetpack without needing to connect to WordPress.com

reCAPTCHA Jetpack vs Unplug Jetpack